Witn ebses



2 Sheets-Sheet 1 INVENTEJR:

(-No Model.)

J, P. SMITHERS.

. Electric Lamp. No. 240,781.

Pa tented April 26,1881.

z E E S. E E N W W 2 Sheets-Sheet 2'.

(No Model.)

J. P. SMITHERS.

m 8 6 2 In- D. A d e t n 6 m p L c r b 0 e 1 E m O 4 2 m FIG-3- FIELEI- ENVENTUR:

N. PETERS PHOTO-LITHOGRAPHER. WASMNGTOM o C UNITED STATES PATENT OFFICE.

JOSEPH P. SMITHERS, OF BROOKLYN, NIHV YORK.

ELECTRIC LAMP.

SPECIFICATION forming part of Letters Patent No. 240,781, dated April 26, 1881.

Application filed May .21, 1880.

To all whom at may concern Be it known that I, Josnrn P. SMrrHERs, of Brooklyn. Kings county, New York, have invented certain new and useful Improvements in Electric Lamps, of which the following is a specification.

This invention relates mainly to carbonpoint lamps, but a portion of it is also applicable to incandescent lamps; and my invention aims chiefly to provide an electric lamp of the former class with such regulating mechanism as will be sensitive to slight changes in the carbon points, and cause the same to approach or separate, as their condition may require, by frequent but infinitesimal motions, so as to maintain the "relative positions of the points uniform, and consequently render the light absolutely steady.

The main feature of my invention may therefore be stated to consist in a sensitive electromagnetic device, preferably a galvanometerneedle, operating, by a slight variation in the main current, to close or break a supplementary or secondary circuit or current, which, actin g on an electro-magnet, will stop or start propelling mechanism to move the carbons together or apart in infinitesimal degrees, and thus prevent any variation in the light.

My invention also consits in a rheotomemagnet, or equivalent electromagnetic motor, controlled or operated by said supplementary current and the sensitive contact-breaker, and acting to propel the mechanism of the lamp.

My invention also consits in the form of the mechanism employed, and in minor features, as hereinafter fully set forth.

Figure 1 of the drawings annexed presents a vertical sectional elevation of a focusing point-to-point lamp constructed according to my invention. Fig. 2 is a sectional plan view thereof. Figs. 3 and 4 represent modifications, and Fig. 5 shows my invention applied to an incandescent lamp.

In the lamp illustrated in Figs. 1 and 2 the carbons a a are held in sockets on the ends of arms I) b, which project from an upright, c, of V-section, as seen in Fig. 2, which serves as a supportandguiding-way, on which the arms are free to slide up or down. Behind this guide 0, however, is arranged a screw-spindle, 0, having (No model.)

portions threaded respectively right and left, as illustrated, while each arm is engaged with the respective threaded portions by a half-nut, d (1, so that hence when this spindle is rotated in either direction the carbons will be fed together or moved apart. The relative pitch of the right and left screw-threads on the spindle o is such that the motion given to the positive and negative carbons will be proportioned to their relative wear, as will be readily understood. The half-nuts d d of the sliding arms are pressed into engagement with the screw-spindle by springs c c, as shown, and may be driven out of engagement therewith by pulling the knobs ff, so as to enable either or both arms to be moved freely up or down on the guide to set the carbons at any desired position, after which the nuts may be released and allowed to engage with the screw-spindle, so as to bring the carbons under control of the regulating mechanism which acts through or on the screw-spindle. This screw-spindle, as may be observed, is pivoted at either end on center screws, 9 9, so that its motion may thus be very easy, and furthermore these screws may be adjusted to put a slight degree of friction on the spindle, so that its motion shall not be too easy. Now, this screw-spindle is rotated in either direction to separate or feed the carbons by some form of electro-ma-gnetic motor.

in the drawings, I have shown an electromagnet, h 71,, arranged as a rheotome, or such as used in alarm-bells or similar devices, in which the current to the magnetcoils is established through the armature t and a stop, It, against which the armature retires, so that when the magnet is in circuit a constant and rapid vibration of its armature is produced, the movement of the armature acting to constantly break and close the circuit in a wellknown manner, readily understood from the drawings. As seen in Fig. 1, each of these rheotome-magnets is arranged at opposite sides of a wheel, 1, fixed on the screw-spindle c. The periphery of this wheel is milled with fine serrations or ratchet-teeth, and the outer ends of g the armatures of the magnets are arrangedto act as pawls against the same, so that when the magnet h is in circuit the vibration of its arm a- 5 be reversed and the carbons separated.

ture will turn the wheel with a'step-by-step motion in one direction and feed the carbons together, while, when the magnet h is in circuit, the motion of the wheel and spindle will The armature-pawls move in the direction of tangents or secants relatively to the periphery of the milled or ratchet-wheel I, and when in repose are out of contact with the wheel, so that 1 when either pawl is thrown into action to revolve the wheel it will not be interfered with by the other one.

A most distinctive feature of my invention consists in a galvanometer-needle arranged to 1 act as a regulator of the lamp. This needle is shown at n, and is preferably of the astatic kind, and also preferably surrounded by an iron ring, a, so as to be more sensitive and also unaffected by theadjacent magnets. The

axis of the needle is pivoted on fine points or pivots at either end, and the axis is connected with one end of a fine spiral, m, preferably of silver ribbon, which connects at the opposite end to an adjusting-screw, m. The coil a of the needle is in the main circuit or in circuit 0 of the spiral. One end of the needle has a limited play between two adjustable stop-screws, p p, and when the lamp is in action is normally out of contact with either; but when the deflection of the needle increases beyond acertain degree it makes contact with the stop 2,

and when it falls below a certain degree or when it becomes inactive from a stoppage of the main current, it makes contact with the stop 19. Now, the stop-screw p is connected with thefeeding-magnet it, and the stopp with the separating-magnet h, so that when the needle retires against the one stop by a slight weakening of the current, or, on the other hand, when it is deflected against the other stop by a slight strengthening of the current, either n1 agnet will hence be thrown into circuit,andthus cause asli ghtfeedin g ora separating movement of the carbonsas their condition may require. It will hence be observed that by this mechanism the slightest changes in the carbon points,

causing a slight weakening or strengthening of the current, will suffice to throw the regulating mechanism into action, which, thus producing frequent infinitesimal feeding or sepa- 5 5 rating motions, will accordingly maintain the relative position of the carbons uniform, and consequently render the emission of light absolutely steady; whereas in most of the lamps heretofore produced a considerable variation in the current is necessary to produce a regulating action, and this furthermore is produced at comparatively long intervals, and with a considerable movement of the carbons, which, as is well known, causes a constant va- 6 5 riation and flicker of the light.

It will be observed that by adjusting the stop-screwspp, so as to give the needle greater or less play between them, the regulating mechanism may be made more or less sensitive. It may also be seen that the spiral m, while serving to make a good electrical connection between the needle and the circuit-wire, and permitting the free movement thereof, also acts as a delicate yet effective spring to return the needle against the stop 1) when the current weakens or ceases, and the tension of this spiral may be nicely adjusted by the screw at.

As will be observed from the drawings, the needle n, as well as the separating and feeding magnets, may be said to be situated in a shunt of the main circuit; but this shunt may have the same conductivity as the main circuit, or its resistance may be higher or lower, but is preferably a little higher than the main circuit. These parts may, however, be in circuit with a distinct source of electricity.

In the drawings the non-conducting portions of the insulation is indicated by textured hatching; and it will hence be seen that the screw-spindle 0 is insulated from the frame; that the guide 0 on which the carbon-holding arms slide is in connection with the frame, but that one arm is connected with the spin dle and insulated from the guide and the other arm the reverse.

It will also be seen that one end of the coils of the magnets in It connects to the frame, while the armatures r) i and stops 7t are insulated therefrom, and that the negative binding-post conn ects directly to the frame, while the positive post is insulated therefrom, but connected to one end of the galvanometer-coil, the opposite end of which connects to a contact-spring, r, resting constantly on the spindle. The direction of the currents will therefore be readily understood from the indicatin arrows of the drawings without requiriu g any further description.

The advantage of the screw mechanism shown for regulating the carbons, together with the sliding arms and fixed guide, is, as may be observed, that of simplicity, and that the luminous point is kept at the same focus, which is important for many uses. The main feature of my invention is, however, no way confined to this special mechanism and may of course be used with any suitable mechanism, whether focusing or non-focusing.

I will also state that in lieu of the rheotomemagnets, shown as a motor for the mechanism, any other form of electro-motor may be usedfor instance, a rotary motor with two commutators-one to revolve the motor in one way and the other to reverse, and each connecting to one of the stop-screws of the galvanometer, so as to effect the feeding and separating movements, in substantially the same manner as in the case illustrated.

Again, in lieu of an electro-motor, a mechanical motor may be employedor instance a strong clock-movement, as shown in Fi 3- which may be released or stopped by the an IIO IIS

mature of a small e1ectro-magnet,s, throwninto or outof the circuit by the galvanometer-needle a, as illustrated, the device being in this case sin gle-actin g, or producing feeding movements only.

In Fig. 4 is shown another application of my invention, in which the gravitation of the carbon holder impels a train of gearing in a well-known manner, while the galvanometerneedle is arranged to act as a brake or escapement on the terminal wheel of the train. Hence, when the deflection of the needle is strong the gearing is stopped and the carbon held in proper position, and when the deflection weakens the gearing is released and the carbons allowed to approach. A stop, t, movin g with the needle, acts on the opposite side of the escapement, and prevents any continuous movement of the carbons which would cause them to make actual contact should the current weaken very much or cease altogether.

In Fig. 5 my needle-regulator is shown applied to an incandescent lamp, in which case it acts to momentarily shunt the current into a short-circuit or resistance coil from the incandescent coil or other luminant part by its varying deflection under a variation in the current, and thus prevents the incaiulescenee becoming dangerously high.

Myinvention also contemplates and includes the use of a balanced or sensitively-adjusted electro-magnet armature, arranged as a contact-breaker, in lieu of the magnetic needle a, to throw a motor magnet or regulating-magnet controlling the regulating mechanism into or out of circuit, which is a substitute for the needle, the latter being, however, preferable.

When the magnetic needle is used as described I prei'er not to send the current directly through the needle itself, but through a copper needle or bar moving therewith and making contact with the stops pp.

hat I claim as my invention isl. The combination, with an electric-lamp, of a sensitive electromagnetic device, ar anged in constant circuit with the carbons or luminant part of the lamp, and acting, by the strengthening or weakening of the deflection or attraction of its movable part, to serve as a contact maker and breaker, to throw a motor or regulating-magnet controlling the regulating mechanism into or out of circuit, substantially as herein set forth.

2. An electric lamp constructed with a galvanometer or equivalent sensitive electromagnetic device, having its coil arranged in constant circuit with the luminant part of the lamp and having its needle or movable part acting to make and break an electric circuit, which serves to regulate the luminant part of the lamp, substantially as herein set forth.

8. The combination, in an electric-lamp, of an electro-imignetic motor, normally out of circuit and arranged to propel the regulating mechanism of the lamp, with a circuit breaking and closing device, arranged constantly in the m aiu or luminal circuit and operated, by the variation thereof, to throw the said magnetic motor into or out of circuit, substantially as and for the purpose herein set forth.

JOSEPH P. SMITHEHS.

XVituesses:

CHAS. M. Hreenvs, EDWARD H. WALES. 

